Dental device for controlling the relative position of dentures in the mouth



Apnl 18, 1967 J. P. FRUSH 3,314,152

DENTAL DEVICE FOR CONTROLLING THE RELATIVE POSITION OF DENTURES IN THEMOUTH Filed Sept. 16, 1963 INVENTQR. JUH/V ,9 500514.

United States Patent Ofifice 3,314,152 DENTAL DEVICE FOR CONTROLLING THERELATIVE POSITION OF DENTURES 1N THE MOUTH John P. Frush, 1100 St.Albans Road, San Marino, Calif. 91108 Filed Sept. 16, 1963, Ser. No.309,175 1 Claim. (CI. 32-19) This invention relates to dental devices,and more particularly is an improvement in dental devices such as thosedescribed in US. Patent 3,068,570, for assisting dentists in controllingthe relative position of upper and lower dentures in a patients mouth.

After dentures are placed in a patients mouth, the dentist must grindthe teeth to equilibrate the dentures for proper occlusal balance.

US. Patent 3,068,570 discloses a device in which a contact plate ismounted across the upper denture, and a base member is mounted acrossthe lower denture. A pin or set screw is threaded into an opening in thebase member and extends toward the contact plate. The pin is adjusted sothat when the lower jaw is moved toward the upper, the pin engages thecontact plate just prior to engagement of the teeth. The pin is thenadjusted so the jaws can be brought together until the highest spot onthe teeth contact. A sheet of carbon paper is placed between thedentures to mark the point or points of contact, and they are thenground off properly. The pin is then further retracted so that the nexthighest point or points on the teeth contact, and they are then groundoff. The process is repeated until proper occlusal balance, orequilibration, is attained.

The patented device works satisfactorily, except that it is sometimesdifficult for the dentist to make the small incremental adjustmentsnecessary to achieve the most comfortable fitting of the dentures withina reasonable time.

This invention improves the patented device by providing calibrationmarks on the base plate around the threaded hole, and an indicator markon the threaded pin to show the amount of rotation of the pin relativeto the base member. Thus, by observing the position of the indicatormark on the pin relative to the calibration marks around the hole in thebase member, the dentist can easily make the incremental adjustmentswhich are often required to be only 5 to /8 of a turn of the pin.Preferably, the indicator mark extends longitudinally along the portionof the pin which is threaded into the hole to provide maximum accuracyin adjusting the position of the pin.

In one preferred form, the indicator mark is an elongated longitudinalgroove formed in the external threads on the pin. In another form of theinvention, the intermediate portion of the base member is displacedrelative to its ends toward the contact plate to provide increased roomfor the patients tongue during the fitting process.

These and other aspects of the invention will be more fully understoodby the following detailed description and the accompanying drawings, inwhich:

FIG. 1 is an elevation, partly broken away, showing the presentlypreferred embodiment of the invention mounted on upper and lowerdentures; and

FIG. 2 is a fragmentary view taken on line 22 of FIG. 1.

Referring to the drawing, an elongated base member 10 is rigidly butremovably secured at its ends by plastic dental wax 12 to the lingualsurf-ace of a lower denture 14. As shown best in FIG. 1, theintermediate portion of the base member is convex upwardly so that itscentral portion is elevated above the ends. An elongated externallythreaded set screw of pin 16 is threaded through 3,314,152 Patented Apr.18, 1967 a threaded hole 18 in the center of the base member and extendsupwardly toward a horizontal contact plate 20 secured at itse sides bydental wax 22 to the lingual side of an upper denture 23. A rotatableball 24 is mounted in a recess 26 in the upper end of the pin to form aball joint in which the ball bears against the lower surface of thecontact plate. The lower end of the pin projects below the base memberand includes a transverse slot 28 to facilitate turning of the pin inthe threaded hole.

An elongated longitudinal groove 30 is formed in the external threads onthe pin to serve as an indicator mark. A plurality of radially extendingcalibration marks 32 are formed on the lower surface of the base memberaround the threaded hole. For illustration, sixteen cali bration marksare shown equally spaced around the hole. Of course, any desired numbercan be used. With the example shown in FIG. 2, it is a simple matter toturn the pin exactly of a turn by moving the screw until the indicatormark travels from one calibration mark to an adjacent calibration mark.This permits the pin to be adjusted longitudinally only a fewthousandths of an inch by the dentist to insure proper fitting of thedentures.

The device is used as follows. The contact plate is rigidly butremovably secured by the dental wax to the upper denture 23 as shown inFIG. 1. The base member and pin are rigidly but removably secured bydental wax to the lower denture. The ball bearing end of the pinprojects upwardly toward the lower face of the contact plate. Thedentures are then placed in the patients mouth, and the pin is adjustedso that. when the patient closes and moves the lower jaw in alldirections, the dentures just do not touch. The threaded pin is thenretracted in increments of A of a turn at a time until a high spot orspots on the teeth contact. A sheet of carbon paper is placed betweenthe dentures to mark the point or points of contact, and they are then.ground oif properly to establish a proper balance or equilibration inalteral movement. The threaded pin is then retracted another V or Ms ofa turn. The thread on the pin is relatively fine, say, 32 turns to aninch, so that the pin is retracted only a few thousands of an inch whenrotated to /8 of a turn. The retraction of the pin is not made until thecarbon paper no longer marks high points or contact points between theteeth upon movement of the lower jaw of the patient in all directions.After this condition is obtained, the pin is retracted in increments asdescribed until the next higher spot or contact point is encountered.It, or they are again marked with carbon paper and jaw movement by thepatient. This process is repeated until all high points or contactpoints have been removed by grinding so that the teeth are in contactonly where necessary for proper occlusal balance.

With many dentures, perfect equilibration is accomplished with as littleas of total turn of the threaded pin. This emphasizes how important it.is that the turns be made in small accurate increments to insure propergrinding and fitting of the dentures.

I claim:

Apparatus for controlling the relative position of upper and lowerdentures in a patients mouth, the apparatus comprising upper and lowerdentures, an elongated base member having end portions rigidly andremovably secured to the lower denture, a contact plate having a portionrigidly and removably secured to the upper denture so as to be spacedfrom the base member, the base member having a threaded hole openingtoward the contact plate, a threaded pin screwed into the hole andextending away from the base member toward the contact plate,calibration marks on the base member around the threaded hole, and alongitudinal groove on the pin to serve as an indicator mark which showsthe amount of rotation of the pin relative to the base member, the

3 4 groove extending from the end of the pin remote from 2,301,358 11/1942 Ballard 32-19 the contact plate to the base member. 3,068,570 12/1962 Thompson et a1. 32l9 FOREIGN PATENTS References Cited by theExaminer 115,995 2/1918 Great Britain.

UNITED STATES PATENTS 5 1, 3/1920 Eickhofi a1 ROBERT E. MORGAN, ActingPrimary Examiner.

